I have a cheap Yamaha guitar (one that I take places and don't mind people borrowing - our own Dick Greenhaus once used it at Swinton, DtG's club).
I decided it probably wouldn't do much harm to it if I installed an undersaddle pickup... it just so happened that the amount of plastic I would have had to plane off the bottom of the saddle was exactly the same thickness as the wood in the bottom of the bridge slot.
So I bit the bullet and removed the wood instead, so the pickup now sits directly on the belly of the guitar with the saddle on top.
Amazingly, the volume practically doubled and the tone improved quite remarkably. Okay, it's still not a prized instrument, but far better than when it came out of the factory.
Sorry, Dave, off topic...!! ;o)